JP2019167443A - Epoxy resin composition and prepreg for fiber-reinforced composite material - Google Patents

Abstract

To provide an epoxy resin composition that is excellent in storage stability and is also excellent in heat resistance and an elastic modulus of a cured product and retention of the elastic modulus in a high temperature region while having low-temperature and high-speed curability and to provide a prepreg for a fiber-reinforced composite material that comprises the epoxy resin composition.SOLUTION: The epoxy resin composition includes (A) component, (B) component and (C) component as given below: (A) component: a glycidyl amine type epoxy resin having at least three glycidyl groups in one molecule; (B) component: an epoxy resin having an oxazolidone ring in the molecule; and (C) component: an imidazole compound represented by formula (1).SELECTED DRAWING: None

Description

  The present invention relates to an epoxy resin composition used for a prepreg for a fiber reinforced composite material, and a prepreg for a fiber reinforced composite material using the epoxy resin composition.

  Fiber reinforced composite materials consisting of reinforced fibers and matrix resins are lightweight and have excellent mechanical properties, so they are aerospace applications (aircraft members, etc.), automotive applications (automobile members), sports applications (bicycle members, etc.), general industries Widely used for applications. The fiber reinforced composite material can be obtained by heat-molding a prepreg for fiber reinforced composite material, which is an intermediate material.

  The prepreg is obtained by impregnating a reinforcing fiber with a thermosetting resin or a thermoplastic resin. As the prepreg resin, a thermosetting resin is mainly used from the viewpoint of heat resistance and strength of the fiber reinforced composite material, and the fiber reinforced composite having excellent heat resistance, elastic modulus, low curing shrinkage, chemical resistance, etc. Epoxy resins are most often used because of the material. In particular, 180 ° C. type epoxy resin is often used in applications requiring heat resistance such as aerospace applications and industrial applications.

  However, a general 180 ° C. curable epoxy resin requires heating at 180 ° C. for 2 hours or longer for curing. Therefore, (i) the heating furnace used for molding the prepreg requires sufficient heating capacity, (ii) the molding time is prolonged, (iii) the auxiliary material is required to have the same heat resistance, etc. There exists a problem that the manufacturing cost of a reinforced composite material becomes high.

  As a method for solving this problem, for example, a method is known in which an epoxy resin composition is primarily cured at a low temperature of 80 to 140 ° C. and demolded, and then post-cured at a high temperature of 180 ° C. or more (Patent Document 1). reference). An epoxy resin composition that can be completely cured at 150 ° C. for 60 minutes has also been proposed (see Patent Document 2).

Japanese Patent No. 4396274 Japanese Patent No. 5326435

However, as described in Patent Document 1, in the case of a method in which primary curing at a low temperature and post-curing at a high temperature are combined, two molding curing processes are required. There is a problem of high costs.
Moreover, the epoxy resin composition described in Patent Document 2 requires heating for 60 minutes at a low temperature of 150 ° C., and the production cost is still high. Furthermore, it is difficult for the obtained cured product to achieve heat resistance (specifically, a glass transition point of 180 ° C. or higher) required in the aerospace, automobile, bicycle field and the like.

  The present invention relates to an epoxy resin composition excellent in heat resistance and elastic modulus of a cured product, elastic modulus retention in a high temperature region, and mechanical properties despite having low temperature and high speed curability, and the epoxy resin composition. A prepreg for a fiber-reinforced composite material used is provided.

・・・式（１）
（２） 前記成分（Ａ）と前記成分（Ｂ）の割合が質量比で３０：７０〜４０：６０である、上記（１）に記載のエポキシ樹脂組成物。
（３） 更に、下記成分（Ｄ）を含む、上記（１）または（２）に記載のエポキシ樹脂組成物。
（Ｄ）成分：熱可塑性樹脂
（４） １５０℃で３０分間加熱して得られる硬化物の動的粘弾性試験におけるガラス転移温度が１８０℃以上である、上記（１）から（３）のいずれかに記載のエポキシ樹脂組成物。
（５） １５０℃で３０分間加熱して得られる硬化物の動的粘弾性試験における３５℃での貯蔵弾性率が２，９００ＭＰａ以上、１５０℃での貯蔵弾性率が２，０００ＭＰａ以上である、上記（１）から（４）のいずれかに記載のエポキシ樹脂組成物。
（６） １５０℃で３０分間加熱して得られる硬化物の示差走査熱量測定における反応発熱ピークの半値幅が１２℃以下である、上記（１）から（５）のいずれかに記載のエポキシ樹脂組成物。
（７） 強化繊維とマトリクス樹脂を含むプリプレグであって、マトリクス樹脂が下記（Ａ）成分、（Ｂ）成分および（Ｃ）成分を含んでなるエポキシ樹脂組成物であるプリプレグ。
（Ａ）成分：一分子内に少なくとも３つのグリシジル基を有するグリシジルアミン型エポキシ樹脂
（Ｂ）成分：分子内にオキサゾリドン環を有するエポキシ樹脂（Ｂ）
（Ｃ）成分：式（１）で表されるイミダゾール化合物（Ｃ）

・・・式（１）
（８） 前記成分（Ａ）と前記成分（Ｂ）の割合が質量比で３０：７０〜４０：６０である、上記（７）に記載のプリプレグ。
（９） 前記マトリクス樹脂が更に下記成分（Ｄ）を含む、上記（７）または（８）に記載のプリプレグ。
（Ｄ）成分：熱可塑性樹脂
（１０） 前記強化繊維が炭素繊維である、上記（７）から（９）のいずれかに記載のプリプレグ。 As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by combining a specific epoxy resin, imidazole compound and thermophilic resin, and have completed the present invention. . That is, the gist of the present invention resides in the following (1) to (10).
(1) An epoxy resin composition comprising the following component (A), component (B) and component (C).
(A) Component: Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (C) Component: Imidazole compound represented by formula (1)

... Formula (1)
(2) The epoxy resin composition as described in said (1) whose ratio of the said component (A) and the said component (B) is 30: 70-40: 60 by mass ratio.
(3) The epoxy resin composition according to (1) or (2), further comprising the following component (D).
Component (D): Thermoplastic resin (4) Any of (1) to (3) above, wherein the glass transition temperature in a dynamic viscoelasticity test of a cured product obtained by heating at 150 ° C. for 30 minutes is 180 ° C. or higher. An epoxy resin composition according to claim 1.
(5) The storage elastic modulus at 35 ° C. in a dynamic viscoelasticity test of a cured product obtained by heating at 150 ° C. for 30 minutes is 2,900 MPa or more, and the storage elastic modulus at 150 ° C. is 2,000 MPa or more. The epoxy resin composition according to any one of (1) to (4) above.
(6) The epoxy resin according to any one of (1) to (5) above, wherein the half-value width of the reaction exothermic peak in differential scanning calorimetry of the cured product obtained by heating at 150 ° C. for 30 minutes is 12 ° C. or less. Composition.
(7) A prepreg comprising reinforcing fibers and a matrix resin, wherein the matrix resin is an epoxy resin composition comprising the following components (A), (B) and (C).
Component (A): Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (B)
(C) Component: Imidazole compound (C) represented by formula (1)

... Formula (1)
(8) The prepreg as described in said (7) whose ratio of the said component (A) and the said component (B) is 30: 70-40: 60 by mass ratio.
(9) The prepreg according to (7) or (8) above, wherein the matrix resin further contains the following component (D).
(D) Component: Thermoplastic resin (10) The prepreg according to any one of (7) to (9), wherein the reinforcing fiber is a carbon fiber.

  According to the present invention, an epoxy resin composition excellent in heat resistance and elastic modulus of a cured product, elastic modulus retention in a high temperature region, and mechanical properties despite having low temperature and high-speed curability, and the epoxy resin composition It is possible to provide a prepreg for a fiber-reinforced composite material using a product.

The following definitions of terms apply throughout this specification and the claims.
“Half width of reaction exothermic peak of epoxy resin composition” means the width in the X-axis direction of the peak at a position that is half the height of the reaction exothermic peak measured using a differential scanning calorimeter (DSC) ( Unit: ° C).
The “glass transition point of the cured product” is obtained by cutting a test piece having a length of 55 mm, a width of 12.7 mm, and a thickness of 2 mm from a resin cured product, and using a dynamic viscoelasticity measuring apparatus (DMA) according to ASTM D7028. , Frequency: 1 Hz, temperature rising rate: measured storage elastic modulus (E ′) in bending mode under conditions of 5 ° C./min, plotted log E ′ against temperature, flat region before log E ′ transition And the temperature at the intersection of the tangent at the inflection point in the region where logE ′ is transferred.

・・・式（１） <Epoxy resin composition>
The epoxy resin composition of the present invention is an epoxy resin composition comprising the following component (A), component (B) and component (C).
(A) Component: Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (C) Component: Imidazole compound represented by formula (1) following

... Formula (1)

  The epoxy resin composition of the present invention preferably further contains a thermoplastic resin as the component (D). Moreover, you may contain other components other than (A) component, (B) component, (C) component, and (D) component as needed within the range which does not impair the effect of this invention. Examples of the other components include epoxy resins other than the components (A) and (B), and optional additives that impart a specific function.

<(A) component>
The component (A) is a glycidylamine type epoxy resin having at least three glycidyl groups in one molecule, and is a component that imparts heat resistance necessary for a cured product of the epoxy resin composition.

  Examples of the component (A) include a tetraglycidylamine type epoxy resin and a triglycidylaminophenol type epoxy resin. These may be used individually by 1 type and may use 2 or more types together.

  Examples of commercially available components (A) include Araldite (registered trademark) MY720, MY721, MY9663, MY9634, MY9655, MY0500, MY0510, MY0600, jER (registered trademark) 604, jER630 manufactured by Mitsubishi Chemical Corporation, Sumitomo Chemical Co., Ltd. Examples thereof include, but are not limited to, Sumiepoxy (registered trademark) ELM-434 and ELM-100.

<(B) component)>
(B) A component is an epoxy resin which has an oxazolidone ring in a molecule | numerator, and is a component which gives high toughness to the hardened | cured material of an epoxy resin composition.

  (B) As a commercial item of a component, TSR-400 made from DIC is mentioned, for example.

<(C) component>
The component (C) is 2-phenyl-4,5-dihydroxymethylimidazole represented by the following formula (1).

・・・式（１） Component (C) is an epoxy resin curing agent and curing catalyst, and is a component that is excellent in pot life at room temperature and imparts high heat resistance and high toughness to the cured epoxy resin.

... Formula (1)

  Examples of the commercially available component (C) include 2PHZ-PW manufactured by Shikoku Kasei Kogyo Co., Ltd.

<(D) component>
(D) A component is a thermoplastic resin. In addition to imparting high toughness to the cured product of the epoxy resin composition, the component (D) suppresses stickiness of the epoxy resin composition to adjust the tack of the prepreg to an appropriate level, or at high temperature, the resin flow immediately before curing. It has the effect of suppressing.

  Examples of the component (D) include polyether sulfone, polyvinyl formal, phenoxy resin, polyamide, acrylic block copolymer, and the like. These may be used individually by 1 type and may use 2 or more types together.

  (D) Component commercial products include PES5003MPS manufactured by Sumitomo Chemical, Ultrason E2020P-SRmicro manufactured by BASF, Virantage VW-10200 manufactured by Slovay, Vinylec E manufactured by Chisso, YP-70 manufactured by Nippon Steel & Sumitomo Chemical, YP-50, EMS Chemie 2AP0-35, TR55, TR90, Evonik Vestosint 2158, 2159, Alkema M52N, M22N, etc. are mentioned, but are not limited thereto.

<Other epoxy resins>
In addition to adjusting the viscosity of the epoxy resin composition, the tack and draping properties of the fiber-reinforced composite material prepreg, the epoxy resins (A) and (B) are used for the purpose of imparting appropriate toughness to the cured epoxy resin. ) An epoxy resin other than the component can be added as necessary.

  For example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, phenol novolac type, cresol novolac type glycidyl ether resin, naphthalene type, dicyclopentadiene type glycidyl ether resin and the like are preferable. These may be used individually by 1 type and may use 2 or more types together.

  Other commercially available epoxy resins include jER (registered trademark) 828, 827, 807, 1001, 1002, 1004, 4004, 4007, 1032H60 manufactured by Mitsubishi Chemical Corporation, EPICLON (registered trademark) 830, 850, N673 manufactured by DIC. , N675, N770, N775, HP4032, HP4700, HP4770, EXA-1514, Tactix (registered trademark) 742, 556 manufactured by Huntsman Advanced Materials, etc., but are not limited thereto.

<Other additives>
Known additives (fillers, diluents, solvents, pigments, plasticizers, antioxidants, stabilizers, etc.) can be added to the epoxy resin composition of the present invention as necessary.

  Examples of the pigment include carbon black and graphene. Carbon black and graphene have the effect of coloring the epoxy resin black, hiding the color of the resin when the fiber reinforced composite material described later is formed, and giving a high-grade appearance especially when applied to sports products. In addition, it has ultraviolet absorption capability and heat dissipation function.

<Resin composition>
In the epoxy resin composition of the present invention, the component (A), the component (B), and the component (C) are essential. It is preferable that the ratio of the said component (A) and the said component (B) is 30: 70-40: 60 by mass ratio. If content of (A) component is the said mass ratio, the heat resistance of the hardened | cured material of an epoxy resin composition will increase. Moreover, if content of (B) component is the said mass ratio, the breaking elongation of the hardened | cured material of an epoxy resin composition will become enough. The content of the component (C) is 100% by mass of the total mass of all the epoxy resins contained in the epoxy resin composition (that is, the total of the components (A), (B), and other epoxy resins). Therefore, it is preferable to add 2% by mass or more, and more preferably 3% by mass or more. If content of (C) component is 2 mass% or more, sufficient heat resistance can be given to the hardened | cured material of an epoxy resin composition. The content of the component (D) is 2% with respect to 100% by mass of all the epoxy resins contained in the epoxy resin composition (that is, the total of the components (A), (B), and other epoxy resins). -30 mass% is preferable, and 3-20 mass% is more preferable. If content of (D) component is 2 mass% or more, sufficient toughness can be given to an epoxy resin. If it is 30% by mass or less, the reinforced fiber can be sufficiently impregnated with the epoxy resin composition for use as a prepreg for a fiber reinforced composite material, and an appropriate surface tack is given when a prepreg for a fiber reinforced composite material is obtained. be able to.

<Half width of reaction exotherm>
The half width of the reaction exotherm (Heat Flow) in differential scanning calorimetry (DSC) of the epoxy resin composition is preferably 12 ° C. or less, and more preferably 10 ° C. or less. When the half-value width of the reaction exotherm is 10 ° C. or less, the epoxy resin composition is excellent in rapid curability and imparting heat resistance to the cured product.

<Glass transition point of cured product>
As for the glass transition point by the dynamic viscoelasticity measurement of the hardened | cured material obtained by heating an epoxy resin composition for 30 minutes at 150 degreeC, 180 degreeC or more is preferable. If the glass transition point of hardened | cured material is 180 degreeC or more, it has sufficient heat resistance for an aircraft use, a motor vehicle use, and a bicycle use.

<Effect>
Since the epoxy resin composition of the present invention described above includes the components (A), (B), (C), and (D) described above, it has low temperature and high speed curability. Specifically, the epoxy resin composition is sufficiently cured by heating at 150 ° C. within 30 minutes.
Moreover, the epoxy resin composition of this invention is excellent in the heat resistance of hardened | cured material, the elasticity modulus maintenance in a high temperature area | region, and a mechanical characteristic. Regarding heat resistance, specifically, the cured product has a glass transition point of 180 ° C. or higher by curing at 150 ° C. for 30 minutes. Specifically, the elastic modulus retention in the high temperature region is as follows. The storage elastic modulus of the cured product obtained by curing at 150 ° C. for 30 minutes is 2,000 MPa or more at 150 ° C. Regarding mechanical properties, the elongation at break in a three-point bending test of a cured product obtained by curing at 150 ° C. for 30 minutes is 5% or more.

・・・式（１）
（Ｄ）成分：熱可塑性樹脂 <Prepreg>
The prepreg of the present invention is an prepreg containing reinforcing fibers and a matrix resin, and the matrix resin is an epoxy resin composition comprising the following components (A), (B), (C) and (D). And the epoxy which contains the said component (A) 30-30 mass parts and the said component (B) 25-55 mass parts in 100 mass parts of all the epoxy resins contained in the said epoxy resin composition. It is a prepreg which is a resin composition.
Component (A): Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (B)
(C) Component: Imidazole compound (C) represented by formula (1)

... Formula (1)
(D) component: thermoplastic resin

<Reinforcing fiber>
Examples of the reinforcing fiber include carbon fiber, aramid fiber, nylon fiber, high-strength polyester fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferable from the viewpoint of excellent flame retardancy, and carbon fiber is particularly preferable from the viewpoint of excellent specific strength and specific elasticity. Examples of the form of the reinforcing fiber include those that are aligned in one direction, woven fabric, non-crimp fabric, and non-woven fabric.

15-65 mass% is preferable and, as for the content rate of the epoxy resin composition in the prepreg for fiber reinforced composite materials of this invention, 20-60 mass% is more preferable.
The prepreg for fiber-reinforced composite material of the present invention can be produced by a known method using the epoxy resin composition of the present invention and reinforcing fibers.

  Since the prepreg for fiber-reinforced composite material of the present invention described above contains the epoxy resin composition of the present invention, it can be cured at a low temperature (150 ° C.) and in a short time (30 minutes). However, it has room temperature storage stability for more than one month. Further, the cured product exhibits a high glass transition point (180 ° C. or higher), and is excellent in heat resistance, elastic modulus retention in a high temperature region, and mechanical properties.

<Fiber reinforced composite material>
The fiber reinforced composite material in the present invention can be produced by a known method using the prepreg of the present invention. For example, there is a method in which a prepreg is sandwiched between a lower mold and an upper mold having a predetermined surface shape, and a cured product having a desired shape is obtained by pressing and heating. Since the fiber-reinforced composite material in the present invention is formed by curing the prepreg of the present invention, it is excellent in heat resistance, elastic modulus retention in a high temperature region, and mechanical properties.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

<Each component>
(A) Component As the component (A), the following compounds were used.
A-1: Triglycidyl-p-aminophenol (MY0510 manufactured by Huntsman Advanced Materials).
A-2: Tetraglycidyldiaminodiphenylmethane (Mitsubishi Chemical Corporation: jER604).

(B) Component The compound shown below was used as (B) component.
・ Oxazolidone ring-modified epoxy resin (DIC-made TSR-400)

(C) Component The compound shown below was used as (C) component.
C-1: 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW manufactured by Shikoku Chemicals).
C-2: 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ-PW manufactured by Shikoku Chemicals).
C-3: 1- (4,6-diamino-s-triazin-2-yl) ethyl-2-methylimidazole (2MZA-PW manufactured by Shikoku Chemicals).

(D) Component The compound shown below was used as (D) component.
D-1: Polyether sulfone (Sumitomo Chemical Co., Ltd. Sumika Excel PES5003MPS).
D-2: Polyvinyl formal (Vinylec E manufactured by Chisso Corporation).

(Other epoxy resins)
As other epoxy resins, the following compounds were used.
・ Liquid bisphenol A type epoxy resin (JER828 manufactured by Mitsubishi Chemical Corporation)
・ Solid bisphenol A type epoxy resin (Mitsubishi Chemical Corporation jER1002)
・ Solid bisphenol F epoxy resin (jER4004 manufactured by Mitsubishi Chemical Corporation)
Solid cresol novolac type epoxy resin (EPICLON N673 manufactured by DIC)
・ Solid phenol novolac epoxy resin (EPICLON N775 manufactured by DIC)
・ Solid polyfunctional naphthalene type epoxy resin (EPICLON HP4770 manufactured by DIC)
・ Solid bisphenol S type epoxy resin (EXA1514 manufactured by DIC)

<Measurement / Evaluation>
(Production of resin plate)
The epoxy resin composition is injected between two 4 mm-thick glass plates that have been subjected to mold release treatment via a 2 mm-thick polytetrafluoroethylene (PTFE) spacer and heated at 150 ° C. for 30 minutes to form a cured resin plate. Obtained. This was used as a resin base plate for three-point bending properties and glass transition point measurement.

(Measurement of reaction calorific value)
1-10 mg of the epoxy resin composition before curing is collected (measurement is possible if the amount in this range is collected), and using a differential scanning calorimeter (manufactured by TA Instruments, DSC-Q100), The temperature was raised to 300 ° C. at a temperature rising rate of 10 ° C./min, and the reaction calorific value, reaction start temperature, and reaction peak temperature were measured.

(Measurement of half-value width of reaction exothermic peak)
In the above reaction calorific value measurement, the width (° C.) of the peak in the X-axis direction at a position that is half the height of the reaction exothermic peak was determined as the half-value width (° C.) of the reaction exothermic peak.

(Evaluation of bending properties)
A test piece having a length of 60 mm, a width of 8 mm, and a thickness of 2 mm was cut out from the cured resin plate. Using an Instron universal testing machine equipped with a three-point bending jig (3.2 mmR for both indenter and support, distance between supports = 16 times the thickness of the test piece), crosshead speed: 2 mm / min. Point bending properties (bending strength, flexural modulus, bending elongation at maximum load, bending elongation at break) were measured.

(Measurement of glass transition point)
A test piece having a length of 60 mm, a width of 12.7 mm, and a thickness of 2 mm was cut out from the cured resin plate. Using a dynamic viscoelasticity measuring apparatus (manufactured by TA Instruments, "DMA-Q800") according to ASTM D7028, in a bending mode under the conditions of frequency: 1 Hz, temperature rising rate: 5 ° C / min. The storage elastic modulus E ′ was measured. Log E ′ was plotted against temperature, and the temperature at the intersection of the tangent of the flat region before the transition of log E ′ and the tangent at the inflection point of the region of transition of log E ′ was taken as the glass transition point.

<Example 1>
The component (A) and the component (D) were weighed into a glass flask with the composition shown in Table 1, and dissolved and mixed at 140 ° C. to prepare a master batch.
The blended amount of component (B) in Table 1 was weighed and added to the obtained master batch, and stirred and mixed at 140 ° C. This was gradually cooled to 65 ° C., and the components (C) and the remaining components were added in the amounts shown in Table 1, and stirred and mixed until uniform. Thereafter, vacuum degassing was performed to obtain an epoxy resin composition.
Various measurements and evaluations were performed using the obtained epoxy resin composition. The results are shown in Table 1.

<Examples 2 to 5>
Except having changed the quantity of each component into the quantity shown in Examples 2-5 of Table 1, the epoxy resin composition was prepared like Example 1, and each measurement and evaluation were performed. The results are shown in Table 1.

<Comparative Examples 1-14>
Except having changed the quantity of each component into the quantity shown in Table 2, the epoxy resin composition was prepared like Example 1, and each measurement and evaluation were performed. The results are shown in Table 2.

  As is apparent from the results in Table 1, the epoxy resin composition obtained in each example has low temperature and high speed curability, but the cured product has heat resistance, elastic modulus and elastic modulus in a high temperature region. It was excellent in retention and mechanical properties.

On the other hand, as is clear from the results in Table 2, the epoxy resin composition of Comparative Example 1 in which the content of the component (A) is less than 30% had a glass transition point of less than 180 ° C.
The epoxy resin compositions of Comparative Examples 2 to 9 using other epoxy resins instead of the component (B) have any of glass transition point, elastic modulus at 150 ° C., elongation at bending fracture, and storage stability. The result was inferior.
In Comparative Example 10 using 2-phenyl-4-methyl-5-hydroxymethylimidazole as the component (C), the half value width of the reaction exotherm in the differential scanning calorimetry was 12 ° C. or more.
Comparative Example 11 having a small amount of the component (C) 2-phenyl-4,5-dihydroxymethylimidazole not only has a glass transition point of less than 180 ° C., but also has a half-value width of reaction exotherm in differential scanning calorimetry. It was over ℃.
Comparative Example 12 using 2MZA-PW instead of 2-phenyl-4,5-dihydroxymethylimidazole as the component (C) results in poor glass transition point and storage stability.
Comparative Example 13 using polyvinyl formal as the component (D) resulted in inferior elasticity retention at high temperatures.
Comparative Example 14 using a bifunctional glycidyl ether type epoxy instead of the glycidyl amine type epoxy resin having a trifunctional or higher glycidyl group as the component (A) results in inferior glass transition point.

  The fiber reinforced composite material obtained by using the epoxy resin composition of the present invention is suitably used for aircraft members, automobile members, bicycle members, sports equipment members, railway vehicle members, ship members, building members, oil risers, etc. Particularly, it is suitably used for aircraft members, automobile members, and bicycle members that require high heat resistance and mechanical properties.

Claims (10)

An epoxy resin composition comprising the following component (A), component (B) and component (C).
(A) Component: Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (C) Component: Imidazole compound represented by formula (1)

... Formula (1)   The epoxy resin composition of Claim 1 whose ratio of the said component (A) and the said component (B) is 30: 70-40: 60 by mass ratio. Furthermore, the epoxy resin composition of Claim 1 or 2 containing the following component (D).
(D) component: thermoplastic resin   The epoxy resin composition according to any one of claims 1 to 3, wherein a glass transition temperature in a dynamic viscoelasticity test of a cured product obtained by heating at 150 ° C for 30 minutes is 180 ° C or higher.   The storage elastic modulus at 35 ° C in a dynamic viscoelasticity test of a cured product obtained by heating at 150 ° C for 30 minutes is 2,900 MPa or more, and the storage elastic modulus at 150 ° C is 2,000 MPa or more. The epoxy resin composition in any one of 4 to 4.   The epoxy resin composition according to any one of claims 1 to 5, wherein a half-value width of a reaction exothermic peak in differential scanning calorimetry of a cured product obtained by heating at 150 ° C for 30 minutes is 12 ° C or less. A prepreg comprising reinforcing fibers and a matrix resin, wherein the matrix resin is an epoxy resin composition comprising the following components (A), (B) and (C).
Component (A): Glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) Component: Epoxy resin having an oxazolidone ring in the molecule (B)
(C) Component: Imidazole compound (C) represented by formula (1)

... Formula (1)   The prepreg of Claim 7 whose ratio of the said component (A) and the said component (B) is 30: 70-40: 60 by mass ratio. The prepreg according to claim 7 or 8, wherein the matrix resin further contains the following component (D).
(D) component: thermoplastic resin   The prepreg according to any one of claims 7 to 9, wherein the reinforcing fibers are carbon fibers.